I remember this talk with @David_AVD last year.Most of the 2-wire strings are wired like this https://auschristmaslighting.com/attachments/16216/
Just taken this string out of an item, sorry it has hot glue marks.I have seen the wiring that Mark_M has just described but it seems to be much less common than the one that I pictured. It is easy to identify which one you have because in the one that I pictured, most of the LEDs have four wires attached to them. In the one that Mark_M pictured, most of the LEDs have two wires attached to them.
In the one that I pictured, when there are more LEDs, the number of LEDs in each section will be increased but there will usually still be approximately 10 sections. In Mark_M's wiring diagram, a string with more LEDs will have more sections.